WGCM Meeting, Dubrovnik, 18-20 October 2015  

Solar Forcing for CMIP6

Katja Matthes1,2 and Bernd Funke3

1GEOMAR Helmholtz Centre for Ocean Research Kiel, Germany 2Christian-Albrechts Universität zu Kiel, Kiel, Germany

3Instituto de Astrofísica de Andalucía, CSIC, Granada, Spain

Overview

•  New reference SSI/TSI (and particle) forcing •  Future solar (SSI and particle) forcing

•  Final comments (solar forcing in PI control, solar ozone forcing)

2

Relative Contribution to TSI

New SSI Reference!

-100

-50

0

50

100

150

200

6 S

SI

/ 6

TS

I [in

per

cent

]

200-400 400-700 700-1000 1000-2430

NR

LSS

IS

ATIR

EC

OS

IO

AR

SC

IAM

AC

HY

SO

RC

E

SU

SIM

WR

-2002

SO

RC

E reanalysis

NRLSSISATIRECOSIOARSCIAMACHYSORCE

WR-2002SUSIM

SORCE reanalysis

Ermolli, Matthes, Dudok de Witt et al., ACP (2013)

NRLSSI1 = standard so far (CMIP5, CCMVal, CCMI)

merged SATIRE+ NRLSSI2 = new reference data set

0.1

1

10

100

Pre

ssu

re (

hP

a)

GEOSCCM NRLSSIGEOSCCM SORCEIC2D NRLSSIIC2D SORCEEMAC!FUB NRLSSIEMAC!FUB SORCEWACCM NRLSSIWACCM SORCEWACCM* NRLSSIECHAM6 NRLSSIHadGEM3 SORCEMMM NRLSSIMMM SORCE

!0.6 !0.4 !0.2 0 0.2 0.4 0.6

20

25

30

35

40

45

50

55

60

Heig

ht

(km

)

Shortwave Heating Rate

Stronger SSI forcing leads to stronger SW HR and temperature response!

SSI Impact on Atmospheric Response

Temperature

Ermolli, Matthes, Dudok de Witt et al., ACP (2013)

New TSI Reference Value

5  

New TSI value 1360.8 ± 0.5 W m−2

Old TSI value 1365.4 ± 1.3 W m−2 (Kopp and Lean, 2011; Ermolli et al., 2013)

Courtesy T. Dudok de Wit (2015)

New CMIP6 Reference Dataset

6  

1850 1900 1950 2000 2050 2100

CMIP6 solar forcing: one netcdf file SSI, TSI, F10.7cm, kp, ap, GCR, protons daily resolution, 1850-2300, 2 scenarios (ref, extreme min)

particle forcing: auroral electrons, solar protons, galactic cosmic rays

radiative forcing: TSI, SSI, F10.7cm

7  

Two Future Scenarios

Reference future scenario  

Extreme Maunder Minimum future scenario  

Courtesy T. Dudok de Wit (2015)

TSI: NRLSSI (ext=red, ref=black), SATIRE (ext=blue)

1 Jan1850

1 Jan1978

1 Jan2106

1 Jan2234

1359.5

1360.0

1360.5

1361.0

1361.5

1362.0

W/m

2

8  

Two Future Scenarios

Reference future scenario  

Extreme Maunder Minimum future scenario  

1850 1980 2100 2300

9  

CMIP6 Solar Forcing

Current status CMIP6 solar forcing dataset: Option1: Reconstruction based on empirical scaling (sunspot number – solar modulation potential) (ready, grey curve above) Option2: Merged SSI/TSI dataset from NRLSSI2 and SATIRE-S models

(SATIRE-S ready, NRLSSI2 almost)

CMIP5  

CMIP6  

SATIRE-TS  

NRLSSI2  

Summary

•  New reference SSI/TSI (+particle forcing) dataset ready by January 1st 2016 (1nm, daily resolution, 1850-2300, one netcdf file)

•  Will be validated in lbl and climate model simulations

(part of CMIP6 solar forcing special issue)

10  

Final Remarks

•  Solar forcing for PI control experiment:

²  One constant value for TSI and SSI spectrum representative for 1850 solar cycle mean conditions

²  Optional: second PI control with solar cycle

variability but no long-term trend included

•  Solar ozone forcing timeseries is coordinated with CCMI ozone dataset (M. Hegglin)

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